linux/include/linux
Kees Cook f06295b44c ELF: implement AT_RANDOM for glibc PRNG seeding
While discussing[1] the need for glibc to have access to random bytes
during program load, it seems that an earlier attempt to implement
AT_RANDOM got stalled.  This implements a random 16 byte string, available
to every ELF program via a new auxv AT_RANDOM vector.

[1] http://sourceware.org/ml/libc-alpha/2008-10/msg00006.html

Ulrich said:

glibc needs right after startup a bit of random data for internal
protections (stack canary etc).  What is now in upstream glibc is that we
always unconditionally open /dev/urandom, read some data, and use it.  For
every process startup.  That's slow.

...

The solution is to provide a limited amount of random data to the
starting process in the aux vector.  I suggested 16 bytes and this is
what the patch implements.  If we need only 16 bytes or less we use the
data directly.  If we need more we'll use the 16 bytes to see a PRNG.
This avoids the costly /dev/urandom use and it allows the kernel to use
the most adequate source of random data for this purpose.  It might not
be the same pool as that for /dev/urandom.

Concerns were expressed about the depletion of the randomness pool.  But
this patch doesn't make the situation worse, it doesn't deplete entropy
more than happens now.

Signed-off-by: Kees Cook <kees.cook@canonical.com>
Cc: Jakub Jelinek <jakub@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Ulrich Drepper <drepper@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-08 08:31:12 -08:00
..
amba
byteorder byteorder: only use linux/swab.h 2009-01-06 18:10:26 -08:00
can
dvb
hdlc
i2c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2009-01-06 17:14:01 -08:00
isdn
lockd
mfd
mlx4
mmc
mtd Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2009-01-07 11:31:52 -08:00
netfilter
netfilter_arp
netfilter_bridge
netfilter_ipv4
netfilter_ipv6
nfsd nfsd: get rid of NFSD_VERSION 2009-01-07 17:38:32 -05:00
raid
regulator
rtc
spi Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2009-01-07 11:31:52 -08:00
ssb
sunrpc
tc_act
tc_ematch
unaligned
usb USB: musb: use new platform data interface of musb to replace old one 2009-01-07 10:00:06 -08:00
uwb
wimax wimax: export linux/wimax.h and linux/wimax/i2400m.h with headers_install 2009-01-07 10:00:22 -08:00
8250_pci.h
a.out.h
ac97_codec.h
acct.h
acpi_pmtmr.h
acpi.h
adb.h
adfs_fs_i.h
adfs_fs_sb.h
adfs_fs.h
aer.h
affs_hardblocks.h
agp_backend.h
agpgart.h
aio_abi.h
aio.h
amifd.h
amifdreg.h
amigaffs.h
anon_inodes.h
apm_bios.h
apm-emulation.h
arcdevice.h
arcfb.h
async_tx.h
async.h async: Asynchronous function calls to speed up kernel boot 2009-01-07 08:45:46 -08:00
ata_platform.h
ata.h
atalk.h
atm_eni.h
atm_he.h
atm_idt77105.h
atm_nicstar.h
atm_suni.h
atm_tcp.h
atm_zatm.h
atm.h
atmapi.h
atmarp.h
atmbr2684.h
atmclip.h
atmdev.h
atmel_pdc.h
atmel_pwm.h
atmel_serial.h
atmel_tc.h
atmel-mci.h
atmel-pwm-bl.h
atmel-ssc.h
atmioc.h
atmlec.h
atmmpc.h
atmppp.h
atmsap.h
atmsvc.h
attribute_container.h
audit.h
auto_dev-ioctl.h autofs4: improve parameter usage 2009-01-06 15:59:23 -08:00
auto_fs4.h autofs4: make autofs type usage explicit 2009-01-06 15:59:23 -08:00
auto_fs.h
auxvec.h ELF: implement AT_RANDOM for glibc PRNG seeding 2009-01-08 08:31:12 -08:00
ax25.h
b1lli.h
b1pcmcia.h
backing-dev.h
backlight.h
baycom.h
bcd.h
bfs_fs.h
binfmts.h fs/exec.c: make do_coredump() void 2009-01-06 15:59:29 -08:00
bio.h
bit_spinlock.h
bitmap.h
bitops.h
bitrev.h
blkdev.h
blkpg.h
blktrace_api.h
blockgroup_lock.h
bootmem.h
bottom_half.h
bpqether.h
brcmphy.h
bsg.h
buffer_head.h
bug.h
c2port.h
cache.h
can.h
capability.h
capi.h
cciss_ioctl.h
cd1400.h
cdev.h
cdk.h
cdrom.h
cfag12864b.h
cgroup_subsys.h
cgroup.h cgroups: add css_tryget() 2009-01-08 08:31:10 -08:00
cgroupstats.h
chio.h
circ_buf.h
clk.h
clockchips.h
clocksource.h
cm4000_cs.h
cn_proc.h
cnt32_to_63.h
coda_cache.h
coda_fs_i.h
coda_linux.h
coda_psdev.h
coda.h
coff.h
com20020.h
compat.h
compiler-gcc3.h
compiler-gcc4.h
compiler-gcc.h
compiler-intel.h
compiler.h
completion.h
comstats.h
concap.h
configfs.h
connector.h
console_struct.h
console.h
consolemap.h
const.h
cpu.h
cpufreq.h
cpuidle.h
cpumask.h
cpuset.h cpuset: remove remaining pointers to cpumask_t 2009-01-08 08:31:11 -08:00
cramfs_fs_sb.h
cramfs_fs.h
crash_dump.h
crc7.h
crc16.h
crc32.h
crc32c.h
crc-ccitt.h
crc-itu-t.h
crc-t10dif.h
cred.h
crypto.h
cryptohash.h
ctype.h
cuda.h
cyclades.h
cyclomx.h
cycx_cfm.h
cycx_drv.h
cycx_x25.h
dca.h
dcache.h
dcbnl.h
dccp.h
dcookies.h
debug_locks.h
debugfs.h debugfs: add helpers for exporting a size_t simple value 2009-01-07 10:00:16 -08:00
debugobjects.h
delay.h
delayacct.h
device_cgroup.h
device-mapper.h
device.h
devpts_fs.h
dio.h
dirent.h
display.h
dlm_device.h
dlm_netlink.h
dlm_plock.h
dlm.h
dlmconstants.h
dm9000.h
dm-dirty-log.h
dm-io.h
dm-ioctl.h
dm-kcopyd.h
dm-region-hash.h
dma_remapping.h
dma-attrs.h
dma-mapping.h
dmaengine.h
dmapool.h
dmar.h
dmi.h
dn.h
dnotify.h
dqblk_qtree.h
dqblk_v1.h
dqblk_v2.h
dqblk_xfs.h
ds1wm.h
ds1286.h
ds17287rtc.h
dtlk.h
dw_dmac.h
dynamic_printk.h
edac.h
edd.h
eeprom_93cx6.h
efi.h
efs_fs_sb.h
efs_vh.h
eisa.h
elevator.h
elf-em.h
elf-fdpic.h
elf.h
elfcore-compat.h
elfcore.h
elfnote.h
enclosure.h
err.h
errno.h
errqueue.h
etherdevice.h
ethtool.h
eventfd.h
eventpoll.h
exportfs.h
ext2_fs_sb.h ext2: allocate ->s_blockgroup_lock separately 2009-01-08 08:31:00 -08:00
ext2_fs.h ext2: tighten restrictions on inode flags 2009-01-08 08:31:00 -08:00
ext3_fs_i.h
ext3_fs_sb.h ext3: allocate ->s_blockgroup_lock separately 2009-01-08 08:31:00 -08:00
ext3_fs.h ext3: tighten restrictions on inode flags 2009-01-08 08:31:01 -08:00
ext3_jbd.h
f75375s.h
fadvise.h
falloc.h
fault-inject.h
fb.h
fcdevice.h
fcntl.h
fd.h
fddidevice.h
fdreg.h
fdtable.h
fib_rules.h
fiemap.h
file.h
filter.h
firewire-cdev.h
firewire-constants.h
firmware-map.h
firmware.h
flat.h
font.h
freezer.h
fs_enet_pd.h
fs_stack.h
fs_struct.h
fs_uart_pd.h
fs.h async: make the final inode deletion an asynchronous event 2009-01-07 08:47:24 -08:00
fsl_devices.h
fsnotify.h
ftrace_irq.h
ftrace.h
fuse.h
futex.h
gameport.h
gen_stats.h
genalloc.h
generic_acl.h
generic_serial.h
genetlink.h
genhd.h
getcpu.h
gfp.h
gfs2_ondisk.h
gigaset_dev.h
gpio_keys.h
gpio_mouse.h
gpio.h
hardirq.h
hash.h
hayesesp.h
hdlc.h
hdlcdrv.h
hdpu_features.h
hdreg.h
hid-debug.h
hid.h
hiddev.h
hidraw.h
highmem.h
highuid.h
hil_mlc.h
hil.h
hippidevice.h
hp_sdc.h
hpet.h
hrtimer.h
htirq.h
hugetlb.h
hw_random.h
hwmon-sysfs.h
hwmon-vid.h
hwmon.h
hysdn_if.h
i2c-algo-bit.h
i2c-algo-pca.h
i2c-algo-pcf.h
i2c-algo-sgi.h
i2c-dev.h
i2c-gpio.h
i2c-id.h
i2c-ocores.h
i2c-pca-platform.h
i2c-pnx.h
i2c-pxa.h
i2c.h i2c: Drop I2C_CLASS_CAM_DIGITAL 2009-01-07 14:29:17 +01:00
i2o-dev.h
i2o.h
i8k.h
i7300_idle.h
i8042.h
ibmtr.h
icmp.h
icmpv6.h
ide.h
idr.h
ieee80211.h
if_addr.h
if_addrlabel.h
if_arcnet.h
if_arp.h
if_bonding.h
if_bridge.h
if_cablemodem.h
if_ec.h
if_eql.h
if_ether.h
if_fc.h
if_fddi.h
if_frad.h
if_hippi.h
if_infiniband.h
if_link.h
if_ltalk.h
if_macvlan.h
if_packet.h
if_phonet.h
if_plip.h
if_ppp.h
if_pppol2tp.h
if_pppox.h
if_slip.h
if_strip.h
if_tr.h
if_tun.h
if_tunnel.h
if_vlan.h
if.h
igmp.h
ihex.h
in6.h
in_route.h
in.h
inet_diag.h
inet_lro.h
inet.h
inetdevice.h
init_ohci1394_dma.h
init_task.h
init.h
initrd.h
inotify.h
input-polldev.h
input.h
intel-iommu.h
interrupt.h Merge branch 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-01-06 17:10:53 -08:00
io-mapping.h
io.h
ioc3.h
ioc4.h
iocontext.h
ioctl.h
iommu-helper.h
iommu.h
ioport.h resource: allow MMIO exclusivity for device drivers 2009-01-07 11:12:32 -08:00
ioprio.h
iova.h
ip6_tunnel.h
ip_vs.h
ip.h
ipc_namespace.h
ipc.h
ipmi_msgdefs.h
ipmi_smi.h
ipmi.h
ipsec.h
ipv6_route.h
ipv6.h
ipx.h
irda.h
irq_cpustat.h
irq.h
irqflags.h
irqnr.h
irqreturn.h
isa.h
isapnp.h
iscsi_ibft.h
isdn_divertif.h
isdn_ppp.h
isdn.h
isdnif.h
isicom.h
iso_fs.h
istallion.h
ivtv.h
ivtvfb.h
ixjuser.h
jbd2.h
jbd.h jbd: improve fsync batching 2009-01-08 08:31:00 -08:00
jffs2.h
jhash.h
jiffies.h
journal-head.h
joystick.h
kallsyms.h
kbd_diacr.h
kbd_kern.h
Kbuild wimax: export linux/wimax.h and linux/wimax/i2400m.h with headers_install 2009-01-07 10:00:22 -08:00
kbuild.h
kd.h
kdebug.h
kdev_t.h
kernel_stat.h
kernel.h Merge git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6 2009-01-06 17:02:07 -08:00
kernelcapi.h
kexec.h
key-type.h
key.h
keyboard.h
keyctl.h
kfifo.h
kgdb.h
klist.h
kmalloc_sizes.h
kmod.h
kobj_map.h
kobject.h
kprobes.h kprobes: support probing module __exit function 2009-01-06 15:59:21 -08:00
kref.h
ks0108.h
kthread.h
ktime.h
kvm_host.h
kvm_para.h
kvm_types.h
kvm.h
lapb.h
latencytop.h
lcd.h
leds-pca9532.h
leds.h
lguest_launcher.h
lguest.h
libata.h
libps2.h
license.h
limits.h
linkage.h
linux_logo.h
list_nulls.h
list.h
llc.h
lm_interface.h
lmb.h
lockdep.h
log2.h
loop.h
lp.h
lzo.h
m48t86.h
magic.h xen: add xenfs to allow usermode <-> Xen interaction 2009-01-08 08:30:59 -08:00
major.h
map_to_7segment.h
maple.h
marker.h
math64.h
matroxfb.h
mbcache.h
mbus.h
mc6821.h
mc146818rtc.h
mca-legacy.h
mca.h
mdio-bitbang.h
mdio-gpio.h
memcontrol.h memcg: fix shmem's swap accounting 2009-01-08 08:31:10 -08:00
memory_hotplug.h
memory.h
mempolicy.h
mempool.h
memstick.h
meye.h
migrate.h
mii.h
minix_fs.h
miscdevice.h
mISDNdsp.h
mISDNhw.h
mISDNif.h
mm_inline.h inactive_anon_is_low: move to vmscan 2009-01-08 08:31:07 -08:00
mm_types.h
mm.h
mman.h
mmdebug.h
mmiotrace.h
mmtimer.h
mmu_notifier.h
mmzone.h mm: introduce zone_reclaim struct 2009-01-08 08:31:07 -08:00
mnt_namespace.h
mod_devicetable.h
module.h module: add within_module_core() and within_module_init() 2009-01-06 15:59:20 -08:00
moduleloader.h
moduleparam.h
mount.h
mpage.h
mqueue.h
mroute6.h
mroute.h
msdos_fs.h
msg.h
msi.h
mtio.h
mutex-debug.h
mutex.h
mv643xx_eth.h
mv643xx_i2c.h
mv643xx.h
n_r3964.h
namei.h
nbd.h
ncp_fs_i.h
ncp_fs_sb.h
ncp_fs.h
ncp_mount.h
ncp_no.h
ncp.h
neighbour.h
net.h
netdevice.h
netfilter_arp.h
netfilter_bridge.h
netfilter_decnet.h
netfilter_ipv4.h
netfilter_ipv6.h
netfilter.h
netlink.h
netpoll.h
netrom.h
nfs2.h
nfs3.h
nfs4_acl.h
nfs4_mount.h
nfs4.h nfsd: last_byte_offset 2009-01-07 17:38:31 -05:00
nfs_fs_i.h
nfs_fs_sb.h
nfs_fs.h
nfs_idmap.h
nfs_iostat.h
nfs_mount.h
nfs_page.h
nfs_xdr.h
nfs.h
nfsacl.h
nfsd_idmap.h
nl80211.h
nls.h
nmi.h
node.h
nodemask.h
notifier.h
nsc_gpio.h
nsproxy.h
nubus.h
numa.h
nvram.h
of_device.h
of_gpio.h
of_i2c.h
of_platform.h
of_spi.h
of.h
oom.h
oprofile.h
oxu210hp.h usb host: Oxford OXU210HP HCD driver. 2009-01-07 09:59:50 -08:00
page_cgroup.h memcg: synchronized LRU 2009-01-08 08:31:05 -08:00
page-flags.h
page-isolation.h
pageblock-flags.h
pagemap.h
pagevec.h
param.h
parport_pc.h
parport.h
parser.h
patchkey.h
path.h
pci_hotplug.h PCI hotplug: introduce functions for ACPI slot detection 2009-01-07 11:13:11 -08:00
pci_ids.h
pci_regs.h PCI: pciehp: cleanup register and field definitions 2009-01-07 11:13:22 -08:00
pci-acpi.h PCI hotplug: introduce functions for ACPI slot detection 2009-01-07 11:13:11 -08:00
pci-aspm.h
pci.h x86/PCI: Do not use interrupt links for devices using MSI-X 2009-01-07 11:13:25 -08:00
pcieport_if.h
pda_power.h
percpu_counter.h Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-01-06 17:10:04 -08:00
percpu.h
personality.h
pfkeyv2.h
pfn.h
pg.h
phantom.h
phonedev.h
phonet.h
phy_fixed.h
phy.h
pid_namespace.h pid: generalize task_active_pid_ns 2009-01-08 08:31:12 -08:00
pid.h pid: implement ns_of_pid 2009-01-08 08:31:12 -08:00
pim.h
pipe_fs_i.h
pkt_cls.h
pkt_sched.h
pktcdvd.h
platform_device.h
plist.h
pm_qos_params.h
pm_wakeup.h
pm.h
pmu.h
pnp.h
poison.h
poll.h poll: allow f_op->poll to sleep 2009-01-06 15:59:12 -08:00
posix_acl_xattr.h
posix_acl.h
posix_types.h
posix-timers.h
power_supply.h
ppdev.h
ppp_channel.h
ppp_defs.h
ppp-comp.h
prctl.h
preempt.h
prefetch.h
prio_heap.h
prio_tree.h
proc_fs.h
profile.h
proportions.h
ptrace.h
pwm_backlight.h
pwm.h
qnx4_fs.h qnx: include <linux/types.h> for definitions of __[us]{8,16,32,64} types 2009-01-07 21:44:20 +01:00
qnxtypes.h qnx: include <linux/types.h> for definitions of __[us]{8,16,32,64} types 2009-01-07 21:44:20 +01:00
quicklist.h
quota.h
quotaops.h
radeonfb.h
radix-tree.h
raid_class.h
ramfs.h
random.h
ratelimit.h
raw.h
rbtree.h
rcuclassic.h
rculist_nulls.h
rculist.h
rcupdate.h
rcupreempt_trace.h
rcupreempt.h
rcutree.h
reboot.h
reciprocal_div.h
regset.h
reiserfs_acl.h
reiserfs_fs_i.h
reiserfs_fs_sb.h
reiserfs_fs.h
reiserfs_xattr.h
relay.h
res_counter.h memcg: memory cgroup resource counters for hierarchy 2009-01-08 08:31:05 -08:00
resource.h
resume-trace.h
rfkill.h
ring_buffer.h
rio_drv.h rapidio: remove excess kernel-doc notation 2009-01-06 15:59:28 -08:00
rio_ids.h
rio_regs.h
rio.h
rmap.h
romfs_fs.h
root_dev.h
rose.h
route.h
rslib.h
rtc-v3020.h
rtc.h
rtmutex.h
rtnetlink.h
rwsem-spinlock.h
rwsem.h
rxrpc.h
sc26198.h
scatterlist.h
scc.h
sched.h Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-01-06 17:10:33 -08:00
screen_info.h
sctp.h
scx200_gpio.h
scx200.h
sdla.h
seccomp.h
securebits.h
security.h
selection.h
selinux_netlink.h
selinux.h
sem.h
semaphore.h
seq_file_net.h
seq_file.h
seqlock.h
serial167.h
serial_8250.h
serial_core.h
serial_pnx8xxx.h
serial_reg.h
serial_sci.h
serial.h
serialP.h
serio.h
sh_intc.h
shm.h
shmem_fs.h
signal.h
signalfd.h
skbuff.h
slab_def.h
slab.h
slob_def.h
slub_def.h
sm501-regs.h
sm501.h
smb_fs_i.h
smb_fs_sb.h
smb_fs.h
smb_mount.h
smb.h
smbno.h
smc91x.h
smc911x.h
smp_lock.h
smp.h
smsc911x.h
snmp.h
socket.h
sockios.h
som.h
sonet.h
sony-laptop.h
sonypi.h
sort.h
sound.h
soundcard.h
spinlock_api_smp.h
spinlock_api_up.h
spinlock_types_up.h
spinlock_types.h
spinlock_up.h
spinlock.h
splice.h
srcu.h
stacktrace.h
stallion.h
start_kernel.h
stat.h
statfs.h
stddef.h
stop_machine.h
string_helpers.h
string.h
stringify.h
superhyway.h
suspend_ioctls.h
suspend.h
svga.h
swab.h Fix up 64-bit byte swaps for most 32-bit architectures 2009-01-06 21:17:57 -08:00
swap.h memcg: fix shmem's swap accounting 2009-01-08 08:31:10 -08:00
swapops.h
swiotlb.h
synclink.h
sys.h
syscalls.h
sysctl.h
sysdev.h
sysfs.h
sysrq.h
sysv_fs.h
task_io_accounting_ops.h
task_io_accounting.h
taskstats_kern.h
taskstats.h
tc.h
tcp.h
telephony.h
termios.h
textsearch_fsm.h
textsearch.h
tfrc.h
thermal.h
thread_info.h
threads.h
tick.h
tifm.h
time.h
timer.h
timerfd.h
times.h
timex.h
tiocl.h
tipc_config.h
tipc.h
topology.h
toshiba.h
tracehook.h
tracepoint.h
transport_class.h
trdevice.h
tsacct_kern.h
tty_driver.h
tty_flip.h
tty_ldisc.h
tty.h
typecheck.h
types.h linux/types.h: Don't depend on __GNUC__ for __le64/__be64 2009-01-07 11:27:12 -08:00
uaccess.h
ucb1400.h
udf_fs_i.h
udp.h
uinput.h
uio_driver.h
uio.h
ultrasound.h
un.h
unistd.h
usb_usual.h USB: storage: add last-sector hacks 2009-01-07 10:00:11 -08:00
usb.h USB: remove info() macro from usb.h 2009-01-07 10:00:14 -08:00
usbdevice_fs.h
user_namespace.h
user.h
utime.h
uts.h
utsname.h
uwb.h
vermagic.h
veth.h
vfs.h
via.h
video_decoder.h
video_encoder.h
video_output.h
videodev2.h
videodev.h
videotext.h
virtio_9p.h
virtio_balloon.h
virtio_blk.h
virtio_config.h
virtio_console.h
virtio_net.h
virtio_pci.h
virtio_ring.h
virtio_rng.h
virtio.h
vmalloc.h
vmstat.h
vt_buffer.h
vt_kern.h
vt.h
w1-gpio.h
wait.h
wanrouter.h
watchdog.h
wimax.h wimax: headers for kernel API and user space interaction 2009-01-07 10:00:16 -08:00
wireless.h
wlp.h
wm97xx_batt.h
wm97xx.h
workqueue.h
writeback.h
x25.h
xattr.h
xfrm.h
xilinxfb.h
yam.h
zconf.h
zlib.h
zorro_ids.h
zorro.h
zutil.h